If your horse spends the majority of time outside in wet, rainy conditions, you should check for rain rot often. A visual evaluation does not suffice, especially during the wet winter months when horses have heavy winter coats. A hands-on examination is necessary. An infected horse will have bumps along the back and croup. When pulled, the hair will easily come free leaving an infected, hairless spot of skin. The problem is easily diagnosed this way, but a definitive diagnosis can be made only from taking a culture and having it tested.
The organism dermatophilus congolensis causes rain rot in horses. Dermatophilus congolensis is not a fungus. It is an actinomycetes, which behaves like both bacteria and fungi. A horse who has this organism on his skin may or may not develop a case of rain rot. The condition affects horses, cattle, sheep, and goats, and is rarely found in pigs, dogs, or cats. The natural habitat of dermatophilus congolensis is unknown, but it is believed to live in the soil, though attempts to isolate it from soil have been unsuccessful. It has only been isolated from the skin of various animals and is restricted to the living layers of the epidermis.
These organisms can live in dormancy on the skin for some time, and become active with moisture, high humidity and warm temperatures. During winter it can easily develop when blanketing is prevalent. The blanket warms your horse and also creates a warm, cozy environment for dermatophiles. Both conditions are the perfect environment to grow a flourishing garden of rain rot. Zoospores germinate to produce barbed, threadlike tentacles, which penetrate into the living skin and spread in all directions. The result is an acute inflammatory reaction as in these photos.
On first treatment simply apply Equiderma Skin Lotion and leave on. Do not attempt to remove scabs that are firmly adhered. This is painful for your horse. Let Equiderma Skin Lotion do the work for you. The next day gently hose the area with warm water. You will notice the scabs will slide off easily and the skin underneath will be much less inflamed. Towel dry and re-apply your Equiderma Skin Lotion. Leave on, reapply every other day. You will notice hair growth within 3 days.